Back in 2008, South Carolina transportation officials were itching to do something innovative to curtail the number of serious traffic crashes in their state.
The federal government already had designated South Carolina as one of the states with the highest proportion of traffic fatalities at intersections. So state highway safety officials began working with their counterparts at the Federal Highway Administration (FHWA) to come up with a new, system-wide approach to tackling the problem.
They ended up launching a project, with FHWA’s help, that used complex data analysis to identify the most dangerous intersections statewide. Then they hired a private company to install simple, low-cost fixes, such as larger signs and new pavement markings, at nearly 2,000 locations – the largest such deployment any state had made.
The preliminary results appear to show that those relatively simply fixes are having a big impact. An early analysis of 458 of the intersections that were modified found a 22 percent reduction in crashes overall.
The federal government is helping about two dozen other states to use data-driven information to determine which roads or intersections are the most deadly and to make them safer. Until recently, state transportation officials often addressed those problems on a case-by-case basis, sometimes spending millions of dollars rebuilding a stretch of highway or creating a new traffic lane. But with budgets tight and taxpayers concerned about getting their money’s worth, states are increasingly turning to cheaper, simpler methods to improve road safety.
So instead of just focusing only on an individual location that has had a lot of bad crashes, as they’ve traditionally done, these states are looking at multiple locations that have similar risk characteristics, and figuring out how they can correct the problem system-wide by making improvements cheaply and effectively.
“In the past, a typical safety project in our office would have been adding a signal or left turn lane. That would, on average, have cost a half million dollars per project,” said Joey Riddle, who runs the South Carolina Department of Transportation’s highway safety improvement program. “With this intersections project, we were able to treat 80 locations for the price of one.”
Ways to Cut Crashes
To pay for its low-cost safety fixes, South Carolina dipped into a fund every state receives from the federal Highway Safety Improvement Program. The latest available statistics show that in 2012, there were 30,800 fatal vehicle crashes in the U.S., in which 33,561 deaths occurred, according to National Highway Traffic Safety Administration data.
To trim that total, states have been allotted a total of nearly $10 billion from the federal highway safety fund for more than 12,000 projects over a five-year period. They decide how to spend the money.
The money from the fund doesn’t just target dangerous intersections. It is used to prevent drivers from running off the road by creating fixes such as large signs alerting that a curve is ahead, and from head-on crashes by installing such devices as rumble strips.
States increasingly have chosen to use money from the fund to design “systemic improvement plans” that focus on ways to make modifications to large portions of a road system in a simple way, using low-cost fixes.
Jeff Shaw, the FHWA’s intersection safety program manager, said the agency first started looking for states that were interested in trying this systemic approach in 2007. A small number of states signed on, including South Carolina and Tennessee. Louisiana was also an early participant, but it initially used funds from a different pot of transportation money. Today, about 25 states are working with federal officials on their own systemic plans to reduce traffic fatalities, according to Shaw. Some, including Ohio, Massachusetts and Georgia, are following South Carolina’s lead and honing in on intersections, but on a smaller scale.
Others have focused on crashes caused by cars running off the road. In Kentucky, for example, officials successfully used an anti-skid technology to treat the surfaces on sharp curves and steep hills at more than two dozen sites. At one dangerous curve in Oldham County, the number of crashes plummeted from an average of 18 a year to two.
“No state has tackled this problem to the same extent as South Carolina,” Shaw said. “They continue to be the best example of all the states, in terms of their ambition and the magnitude of their program.”
Shaw said that the systemic approach has changed the way traffic engineers think about highway safety. Historically, they would prioritize sites based on the number of crashes or the severity and then make improvements one at a time.
“You’d try to determine what’s wrong with this location and how can I fix it?” Shaw said. “It’s very time consuming and expensive.”
Shaw said that with the newer approach, transportation officials can analyze data and design a package of low-cost, effective modifications at a large number of hot spots.
“It really has created a whole new paradigm in how we approach traffic safety,” he said. “The idea is to put solutions out there that work and can reduce crashes today, as opposed to waiting for an opportunity to reconstruct or apply an expensive fix over time. There’s no question that this approach can save lives.”
Unlike most states, where counties or local governments control much of the road system, South Carolina maintains 41,000 out of its 66,000 miles of roads. About 96 percent of fatalities occur on state roads, according to the state DOT’s Riddle.
When South Carolina officials decided to target deadly intersections, they worked with the FHWA and a federal contractor to draft a comprehensive analysis of five years of crash data to figure out which of the state’s intersections were the most dangerous.
The state then used a portion of its federal highway safety funds to hire private contractor 3M to make the improvements at nearly 2,000 intersections, at an average cost of about $6,000 each. Among the changes: It erected oversized yellow, diamond-shaped advance warning signs on the left and right sides of the road ahead of intersections, some with solar-powered flashers mounted on top. It created new pavement markings and installed one traffic signal light per lane at some intersections. The federally funded project, which ended in 2013, cost a total of $12 million over three years.
Riddle said that the state chose not to do the work in-house because of the project’s magnitude and the contractor’s ability to do the job quickly. He said it would have taken 20 years to make all the changes using state workers.
But it wasn’t always smooth sailing.
Some local residents were furious about the changes. They didn’t like the large, brighter double signs so close to their property. They complained that they were eyesores. “People were saying we don’t want it," Riddle said. "It’s really ugly. A lot of local politicians got involved because they were hearing from constituents.”
In Aiken, South Carolina, some city leaders argued that the new signs didn’t fit in with the historic district. One local congressman even wrote to the state DOT asking that the signs at nine intersections downtown be removed.
Controversy also erupted in some coastal areas, when contractors tried to install the oversized signs and trim 100-year-old trees to improve sight lines. “Charleston and Hilton Head spend a lot of money trying to hide signs. Our big yellow fluorescent signs did not go over well,” Riddle said.
State transportation officials ended up reducing the size and number of signs in some areas and making other concessions. Over time, Riddle said, residents began to accept that while they might not like the changes, they were needed to prevent crashes and deaths.
“People just want to have things explained to them. You can talk them off the cliff,” Riddle said. “It was a public safety problem.”
A Different Approach
In Minnesota, state transportation officials have taken a different approach to reducing crashes.
Instead of relying on data only to identify the most dangerous spots, they also used it to come up with a variety of risk factors that would help predict which intersections, roads and curves would have the highest potential for serious crashes.
“We’re really good at reacting. Crashes occurred and we wanted to respond to that, historically,” said Brad Estochen, state traffic safety engineer for the Minnesota Department of Transportation. “Now, we’re trying to do some things up front so we can prevent those crashes from occurring.”
Estochen said his department, which consulted with the local FHWA engineer but acted independent of the federal agency, distributed the information it compiled from its data analysis to all 87 counties. The reports showed which locations were at risk for the most crashes and fatalities. The 85 counties that were interested in following up received a total of $65 million from the state’s federal highway safety funds to make low-cost improvements, such as new signs and pavement markings, street lights and rumble strips.
“I think other states and localities are going to start embracing this, to do a little bit of prevention,” Estochen said.
The number of fatal crashes in Minnesota has dropped, he said, from 371 in 2009, when the program started, to 357 in 2013. But he cautioned that state officials are trying to do a formal evaluation to determine how much of an impact the traffic modifications may have had on those numbers.
Looking Good So Far
Preliminary results from South Carolina’s intersection safety program are highly encouraging, transportation experts say.
Besides the 22 percent reduction in crashes overall in the sampling of intersections that were modified, at intersections without traffic signals, crashes dropped 34 percent and at night, they fell nearly 43 percent, according to Melissa Blakely, a regional manager at 3M’s traffic safety division. “It reduced crashes and is saving lives,” she said.
All of the data from South Carolina are now being examined more extensively by the federal government, as is information from other states’ highway safety projects.
The research, conducted by experts, is paid for by 38 states and the federal government, which pool their money. Experts perform in-depth statistical analyses examining data from three years before and after the safety improvements were made. They look at many factors, including how much traffic was on the road, weather conditions and drivers’ sobriety levels.
The federal government then publishes reports showing which strategies reduce crashes, are cost-effective and save lives, said Roya Amjadi, a specialist at FHWA who oversees the analyses. She noted that research already has proven that spending a small amount of money on signs and pavement markings can reduce crashes considerably.
“The pool study helps us figure out if we want to continue doing these types of projects, or if we didn’t get that much bang out of our buck, whether we should do something else,” said Dan Hinton, an FHWA safety and traffic operations engineer in South Carolina.
Hinton said that while the federal research is still ongoing, the initial data from the South Carolina project looks promising.
The FHWA’s Shaw is even more enthusiastic. “It absolutely has been a success,” he said. “I’m very confident that the numbers (from the federal analysis) are going to be very good in the end, based on the preliminary reductions in the number of crashes.”
South Carolina DOT’s Riddle said that although he’s taking a wait-and-see approach until the federal review is completed, he is optimistic that the results are going to show that the program worked.
“I’ve been involved in safety for 20 years and this is the best thing that I’ve ever done,” Riddle said.
Stateline is a nonpartisan, nonprofit news service of the Pew Charitable Trusts that provides daily reporting and analysis on trends in state policy.
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